Obama to unveil final power plant emissions limits Monday, calls it biggest US step on climate

President Barack Obama on Monday will unveil the final version of his unprecedented regulations clamping down on carbon dioxide emissions from existing U.S. power plants.

Obama says it's the biggest and most important step the U.S. has ever taken to combat climate change. He says power plants are the biggest source of harmful, heat-trapping gases but that until now there have been no federal pollution limits.

The president says climate change is no longer a problem for another generation to address.

The finalized rule gives states more time — until 2022 — to comply. But it also requires steeper cuts in overall carbon dioxide emissions than the previous plan.

The Obama administration first proposed the rule last year. Opponents plan to sue immediately to stop the rule's implementation.